Focus on... Horticulture in the city

For the poorest people in the world, wasteland means opportunity, no matter how small the plot. With a little creativity and investment, boxes, tyres, plastic bags and bottles can nurture fresh lettuce, peppers, and a variety of other vegetables and herbs. This month, we focus on the rooftop gardens, backyard enterprises and peri-urban plots that supply fresh produce to the world's cities, and find out why household gardening is the most common form of urban horticulture in the world.

In Kibera, the largest slum in Africa, wastewater irrigation supports crop and fodder production, bringing dignity and hope to many. In Lima's poor quarter of Villa Maria del Triunfo, fresh vegetables are on display at weekly markets, while in Cuba, profits from urban horticulture are ploughed back into community enterprises. We also look at techniques which allow farmers to grow their produce into the hot summer months. From hydroponics to grafting, we discover that such enterprises not only increase food security and fresh produce for the world's burgeoning urban population, but provide a good income for urban growers as well.

Based on a low-cost, low-pressure drip irrigation system, the African market garden project is enabling farmers to better control their use of water and fertilisers, thereby reducing costs and increasing yields.

The majority of urban home-gardening families in Sri Lanka grow for domestic needs. But in semi-urban areas and villages, mangoes and avocadoes are deliberately grown for market. It's all about having the right knowledge.

Tomatoes are popular in Vietnam, and fetch a tidy profit in the market. Grafting tomatoes onto eggplant roots has created a hardier plant which can maintain production for many more months than in the past.

The jasmine industry is a major income earner for the urban and peri-urban poor in the Philippines. However, the industry is beset by bad practices, including overuse of pesticides and poor diversity in its genetic base. UPWARD, a science and development network, is helping to find some solutions.